Light can generate lift

Researchers create a lightfoil that can push small objects sideways

Light has been put to work generating the same force that makes airplanes fly, a study appearing online December 5 in Nature Photonics shows. With the right design, a uniform stream of light has pushed tiny objects in much the same way that an airplane wing hoists a 747 off the ground.

Researchers have known for a long time that blasting an object with light can push the object away. That’s the idea behind solar sails, which harness radiation for propulsion in space, for instance. “The ability of light to push on something is known,” says study coauthor Grover Swartzlander of the Rochester Institute of Technology in New York.

Light’s new trick is fancier than a boring push: It created the more complicated force called lift, evident when a flow in one direction moves an object perpendicularly. Airfoils generate lift; as an engine propels a plane forward, its cambered wings cause it to rise.

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